This invention is directed to a DC motor control circuit, and, in particular, to a control circuit for effecting improved starting and stopping of a DC motor.
Heretofore the use of DC motors and control circuitry for driving the DC motors at constant speeds have been developed. However, the starting and stopping of such constant rotation DC motors has been found to be less than completely satisfactory. For example, when a DC motor is started, in response to a low magnitude voltage, it is difficult to obtain a constant rotational speed immediately after starting. Similarly, when a DC motor is stopped, it is difficult to assure that no rotations are effected immediately after stopping. One type of low magnitude voltage device, wherein a faint voltage signal is utilized to control a DC motor, is a printer. Additionally, scenery cameras, miniaturized information processing instrumentation, such as calculators and other automatic control instruments, all require a low energy, high performance, stable operating constant rotational speed DC motor that has a particularly sensitive start/stop control. Although braking devices can be utilized with the DC motor, such braking devices require additional power consumption to energize the transistorized circuit in order to overcome the braking means when immediate starting is required. Accordingly, a control circuit for effecting improved starting and stopping of a DC motor is desired.